Universal M18 gph measured?

Oct 9, 2008
1,742
Bristol 29.9 Dana Point
This is a very narrow topic so ignore if no M18.
Also boat, weight, etc specific but am wondering about fuel gph for future planning.

Anyway, the boat has an M18 2 cyl 14hp. Good running condition. It seems like it runs on air (like the sails :-D ) for the tank takes a very long time to deplete. I sailed all last season in the east, then we moved to CA in Dec and I've sailed a lot including having to motor half the way from Isthmus Harbor to Dana Point about 4 hours. And I've used it a bunch since. It's a 19 gallon rectangular tank, I haven't filled it since the fall of 2013, and there's still about 7-8 gallons on there (2/5ths).

So I'm a guy who likes to brag about stuff. ;-) Like my stunning motor only uses a quart of diesel an hour, but on serious terms I'd like to analyze others' fuel usage for planning near future long range trips. For I may be overestimating how many hours I've gone through on the fuel. The boat has no fuel gauge, sans a 4 foot dowel that's marked at full, and it would take some long time and doing to go by the hour meter and fill up quantity to get a good average. I should have done it to begin with.

So if someone has an M-18 with approximately a 10000 lb boat wet and geared up, and you have measured flow in a scientific fashion, can you display your numbers ?

Long wind for what's your gph sorry.
 
Oct 6, 2009
129
Newport Newport 28 MKII Jacksonville, FL
The previous owners of my 1986 Newport 28 MKII with the M18 sailed it to the Bahamas and Abacos and ended up motoring it all the way back to Jacksonville, FL one summer. Their fuel records in the log claim they burned 1/3 gallon per hour motoring back at 2300 RPM, which is 5 knots on this boat. I have no idea why they motored all the way back. My guess is not much wind or they had a schedule to keep.
 
Jun 5, 2014
209
Capital Yacths Newport MKIII 30 Punta Gorda, Fl
We have a M18, 2 cylinder, 14 HP diesel in our 1987 Newport 30. It weighs in at 8500lbs dry. I'm sure it is probably 10000-11000 lbs with all our stuff in it. We just bought it last April. I am guessing ours uses about 1/4 gal per hour. We have a fuel gauge and had to motor 4 hours recently (NO wind) to get home. We could not even tell the gauge moved after 4 hrs. I know it does seem like it doesn't use very much. However, I am not sure exactly what GPH we get but i am guessing you are probably correct to say 1 quart/hr. :)
 
Jun 11, 2004
1,918
Oday 31 Redondo Beach
On our '85 O'Day 31 with the original M-18 we've burned a little more than 1/4 and a little less than 1/3 gallons per hour (call it 7/24 ths :) ) over the last 500 hours or so.

We probably weigh in just a bit more than you do.